#include<iostream>
#include<queue>
#include<string>
using namespace std;

queue<char> q;
string temp;

int main (void) {
	for (char i = 'a'; i <= 'z'; i++) {
		q.push(i);
	}
	while (!q.empty()) {
		cout << q.front() << endl;
		q.pop(); 
	}

	return 0;
}
